Classified as Vulnerable (VU) on the IUCN Red List (1) and listed on Appendix II of CITES (4).

The soft, short, thick, woolly hair of this primate, after which it is named (2), makes it a particularly attractive New World monkey. The downy fur of the common woolly monkey may vary between shades of dark grey, brown or black (5), and is often darker on the head and slightly lighter on the underparts (3). The face, naked of any fur, is typically black (3). For a tree-dwelling monkey, this species is rather large (3), but it moves easily through the forest using its long limbs and prehensile tail, which has a bare patch near the tip to provide extra grip (2) (3). Male woolly monkeys are larger than females and also have larger canines (5). It was once thought that there were four subspecies of the common woolly monkey: Lagothrix lagotricha lagotricha, L. l. lugens, L. l. cana and L. l. poeppigii (5) (6); however, some now consider these to be full species (1).

The common woolly monkey occurs in South America in the upper Amazon basin (5). Its range extends west from the Rio Tapajos in Brazil, to eastern Peru, Ecuador and Colombia (1) (3). It may also occur in Venezuela (1), but is apparently no longer found in Bolivia, where it is believed to have been extirpated by hunting (5).

Lowland primary forest is the preferred habitat of the common woolly monkey; however, it may also be found in cloud forest, up to elevations of 3,000 metres, and occasionally in disturbed or fragmented areas of forest (1) (3). In certain seasons it may enter flooded forests, to feed on the plethora of fruits that are found there (1).

Like many New World monkeys, this species is diurnal and tree-dwelling (3). Moving about in groups of between 20 and 70 individuals (3), the common woolly monkey feeds primarily on fruits (7). However, young seeds, young leaves and flowers are also eaten at certain times of the year (7). It moves about the trees, with its tail providing a constant safety grip on the branches (2), and sleeps in the topmost layer of the forest, often in the crown of a tall tree (5). Sometimes, however, the common woolly monkey will descend to the ground, where it moves upright on its two hindlegs, using the arms and tail for balance (3).

Within each common woolly monkey group, there is a dominance hierarchy amongst the males, which is decided upon through aggressive behaviour (3). They are polygamous monkeys, meaning that they mate with more than one partner each season (5), and it is believed that the scent-marking observed in this species plays a part in mating activity, by advertising the quality of a male. Males scent mark by either rubbing their chest or anogenital region against a branch or tree trunk (8).

Female common woolly monkeys typically give birth to a single young after a gestation period of between 7 and 7.5 months (3) (5). The mother will feed her young for between 9 and 12 months. Sexual maturity is reached at between five and eight years, and, based on evidence of a captive common woolly monkey, this species may live up to around 24 years (3).

The common woolly monkey is often considered to be one of the primates most vulnerable to hunting in the New World (3) (5). It is valued for its meat, with its large size making it a particularly enticing target, but it is also hunted for its pelt and for the pet trade (3) (5). It is generally a young woolly monkey that is sought for the pet trade, which tragically often involves the mother being killed in order to capture the defenceless infant (3). It has been estimated that for every young woolly monkey that is sold live in a market, at least 10 female woolly monkeys died (3). In addition to the threat of hunting, the common woolly monkey is being threatened by the loss of forests. As humans encroach on this habitat, turning the once biodiverse forest of the Amazon basin into agricultural land (1), the common woolly monkey is one of the first primates to disappear (3).

Despite the gloomy picture painted above, the common woolly monkey does still occur over a wide area, and can be found in a number of remote regions (1), for the time being safe from the expansion of human activities. It also occurs in a number of protected areas such as the Juami-Japurá Ecological Station in Brazil and the Nukak National Natural Reserve in Colombia (1).